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Climate and Terrestrial Biodiversity
Chapter 7
7.1
The Earth Has Many Different
Climates
 Weather – local
area’s short-term
temperature,
precipitation, humidity,
wind speed, cloud
cover, etc.
• Measured over hours
or days
The Earth Has Many Different
Climates
 Climate – area’s
general pattern of
atmospheric or
weather conditions
• Measured over long
periods of time
The Earth Has Many Different
Climates
 Climate - varies over
different parts of the
earth
• Uneven heating of the
earth’s surface by the
sun
• Rotation of the earth
on its axis
• Properties of air,
water, and land
Earth’s Atmosphere
Tropics – air is warm
Equator – 30o N/S
Earth’s Atmosphere
Polar regions – air is cold
60o - 90o N/S
Convection Currents
 Up-and-down movement of air due to
temperature differences
Convection Currents
 Rule: Hot air rises and cold air sinks.
 Equator
• Hot air rises and heads toward the poles
Convection Currents
 Rule: Hot air rises and cold air sinks.
 Poles
• Cold air rushes in to fill the space at the equator
Figure 6.5
Wind
 Horizontal movement of air
Convection Currents + Earth’s Rotation
Equator
Coriolis Effect
 Earth rotates and
causes circulating air
to be deflected
 Causes things thrown
in straight line to
move to the right or
left (depends on
hemisphere)
Imagine a merry-go-round…
Suppose you (represented by the dark blue
circle) and a friend (represented by light blue
circle) are on a merry go round.
You gently toss a ball
towards your friend
The ball doesn’t
actually get there!
Coriolis Effect Summary
 Causes moving objects on Earth to follow curved
paths
• Northern Hemisphere – follows a path to the right
of its intended target
• Southern Hemisphere – follows a path to the left
of its intended target
 Acts on all moving objects
Your Turn!
 Deflected Activity
 Global Wind Patterns
Prevailing Winds
 Major wind patterns on the Earth
 Direction caused by:
1. Convection currents
2. Earth’s rotation from west to east
3. Air pressure
Global Air Circulation
Wind Belts
 Doldrums
• Between 5 degrees
North and 5 degrees
South latitude
• Winds are calm
Wind Belts
 Trade Winds
• Historically: Used by
ships traveling
between Europe and
the Americas
• 5o-30o North and
South of the Equator
Trade Winds
 Northern Hemisphere
• Warm air around the
equator rises and
flows north toward the
pole
• Earth’s rotation
deflects air toward the
right
Trade Winds
 Southern Hemisphere
• Similar pattern
• Winds blow from the
southeast toward the
northwest
• Descend near 30
degrees South latitude
Wind Belts
 Westerly Winds
• Remaining air (air
that does not
descend at 30
degrees North or
South latitude)
continues toward the
poles
Wind Belts
 Polar Easterlies
• Cool air sinks and
moves towards the
equator
• Air is deflected by
Earth’s rotation
Winds Drive Surface Ocean
Currents!
 Global winds drag on
the water’s surface
• Cause water to move
and build up in the
direction that the wind
is blowing
Natural Capital: Generalized Map of the
Earth’s Current Climate Zones
Your Turn!
 Coastal Upwelling
Climate and Biomes
Biotic and Abiotic Factors
 Biotic Factors
• Biological (living)
influences on an
organism within an
ecosystem
• Predators
• Prey
 Abiotic Factors
• Physical (non-living)
factors that shape
ecosystems
• Temperature
• Precipitation
• Humidity
What is a biome?
 Terrestrial community that covers a large area
and is characterized by certain soil and climate
conditions
• Particular assemblages of plants and animals.
Biomes
 Variations in plants and animals
help different species survive
under different conditions in
different biomes.
 Tolerance - ability to survive
and reproduce under conditions
that differ from their optimal
conditions
The Major Biomes
60°N
30°N
0° Equator
30°S
60°S
Tropical rain forest
Tropical dry forest
Tropical savanna
Tundra
Temperate grassland Temperate fore
Northwestern
Desert
coniferous fore
Boreal
forest
Temperate woodland
(Taiga)
and shrubland
Mountains and
ice caps
Biomes
 Large terrestrial regions characterized by similar
climate, soil, plants, and animals
• Location irrelevant
Biomes
 Not uniform; consist of a mosaic of patches with
different biological communities
Generalized Effects of Elevation and
Latitude on Climate and Biomes
Natural Capital: Average Precipitation and
Average Temperature as Limiting Factors
Your Turn!
 Biome Jigsaw
 Biome Bags
Global Air Circulation, Ocean Currents,
and Biomes
Energy Transfer by Convection
in the Atmosphere
 Heat is absorbed and
released more slowly
by water than by land
• Moderate weather and
climate of nearby
lands
Biomes and Climate
 The climate of a region is an important
factor in determining which organisms
can survive there.
• Temperature and precipitation can
vary over small distances.
• Microclimate - the climate in a small
area that differs from the climate
around it
The Earth’s Surface Features Affect
Local Climates
 Cities
• Microclimates
• More haze and smog
• Higher temperatures
• Lower wind speeds
• Causes
• Bricks, asphalt, and
concrete absorb and
hold heat
• Buildings block wind
flow
The Earth’s Surface Features Affect
Local Climates
 Mountains
• Rain shadow effect: moist air blowing inland is forced
upward; cools and expands
• Loses most of its moisture as rain or snow on the
windward slope
• Air dries and warms over leeward side; increases
ability to hold moisture and dries ecosystem
Climate Terms
 Tropical – warm; receives direct or nearly direct
sunlight year round
 Desert - dry
 Temperate – moderate
Climate Graphs of Three Types of
Deserts
Climate Graphs of Tropical, Temperate,
and Cold Grasslands
Chaparral Vegetation in Utah, U.S.
Climate Graphs of Tropical, Temperate,
and Cold Forests
Stratification of Specialized Plant and
Animal Niches in a Tropical Rain Forest
Major Human Impacts on Terrestrial
Ecosystems
Tundra
Taiga
 See Clip
Tropical Rain Forest
Temperate Forest
Temperate Grassland
Desert
Chaparral